Metal plating has been known for many years and is a technique for the application of a thin metallic coating to a substrate. While the use of electroless deposition of metals may be utilized, generally electroplating is the more frequent technique where there is a generation of waste metal ion containing streams. As a portion of the deposition process, metals ions remain in solution which may not deposit onto a substrate. These ions nevertheless are present in the solution and need to be treated so that the resulting solution is environmentally safe and can be subsequently disposed. The coatings of metals by electro-deposition and other processes is substantially described as well known in the field. See Metals Handbook 9th Edition Volume 5, published by the American Society of Metals, 1982. Recovery of metal ions from waste metal plating streams using an electrolytic technique has been described in U.S. Pat. Nos. 4,436,601 and 4,515,672, which are hereby incorporated by reference.
The prior art describes cathodes used in metal ion recovery which may generate impurities in their use such as cathodes based on an organic substance in manufacture which when introduced into plating streams is undesirable.
The prior art likewise is lacking in a disclosure for a convenient mechanism for being able to economically operate recovery of metal values in a waste stream and to reuse those recovered metal values.